engineering electromagnetic wave properties using subwavelength antennas structures

108 Pages·2015·4.7 MB·English

ENGINEERING ELECTROMAGNETIC WAVE PROPERTIES
USING SUBWAVELENGTH ANTENNAS STRUCTURES

Dissertation
Submitted to
The School of Engineering of the
UNIVERSITY OF DAYTON

In Partial Fulfillment of the Requirements for
The Degree
Doctor of Philosophy in Electro-Optics

By
Shiyi Wang

UNIVERSITY OF DAYTON
Dayton, Ohio
May, 2015
ENGINEERING ELECTROMAGNETIC WAVE PROPERTIES
USING SUBWAVELENGTH ANTENNAS STRUCTURES

Name: Wang, Shiyi

APPROVED BY:

____________________________ ____________________________
Qiwen Zhan, Ph.D. Partha Banerjee, Ph.D.
Advisory Committee Chairman Committee Member
Professor Director and Professor
Electro-Optics Program Electro-Optics Program

____________________________ ____________________________
Andrew Sarangan, Ph.D. Imad Agha, Ph.D.
Committee Member Committee Member
Professor Assistant Professor
Electro-Optics Program Physics

____________________________ ____________________________
John G. Weber, Ph.D. Eddy M. Rojas, Ph.D., M.A., P.E.
Associate Dean Dean, School of Engineering
School of Engineering
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© Copyright by
Shiyi Wang
All rights reserved
2015

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ABSTRACT
ENGINEERING ELECTROMAGNETIC WAVE PROPERTIES USING
SUBWAVELENGTH ANTENNAS STRUCTURES

Name: Wang, Shiyi
University of Dayton

Advisor: Dr. Qiwen Zhan
With extraordinary properties, generation of complex electromagnetic field based on novel
subwavelength antennas structures has attracted great attentions in many areas of modern
nano science and technology, such as compact RF sensors, micro-wave receivers and nano-
antenna-based optical/IR devices.
This dissertation is mainly composed of two parts. For the first part, the idea of plasmonic
localization in optical range is transferred and utilized for generating confined fields with
high enhancement in RF range. A subwavelength modified bowtie antenna in RF range is
designed for generating strong broadband field enhancement in its extended feed gap. The
strongly enhanced RF field within the gap can be applied to directly modulate guided
optical wave propagating in a waveguide, which enables to realize indirect RF signal
sensing through photonic methods. Systematic exploration for modified bowtie antennas
and its substrate effect has been given in this part.
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In the second part, the RF antenna design idea is extended to infrared and optical range
based on antenna scaling theory specific for this spectrum. Both transmission and reflection
types of metasurface structures have been designed and proposed to obtain optical needle
field with a flat-top longitudinal intensity of depth of focus 5λ. With fine adjustment of
different nano-antenna structures, both of the metasurfaces enable to generate complex
vectorial field with spatial radial polarization, whose amplitude modulation range covers
0.07 to 1 with binary phase control. Then the scattered field can be tightly focused by a
high numerical aperture (NA) lens in order to generate longitudinally polarized flat-top
field along propagation direction. By exploring the subwavelength antennas’ mechanism
and connections between different frequency regions, this dissertation is expected to
provide general guidance for design and characterization of next-generation
subwavelength antennas structures with extraordinary electromagnetic wave properties.
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Dedicated to my parents and my girlfriend Yijia

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ACKNOWLEDGEMENTS

I am greatly indebted to the people who have helped me over the last four years. Above all,
I would like to acknowledge my advisor, Dr. Qiwen Zhan, for his tremendous amount of
help and support through my Ph.D. period. I couldn’t thank him enough. I would like to
thank him for the great amount of time, effort and thoughts he put in my research and for
the inspiring discussions and interactions with him, which leads to the successful
conclusion of my dissertation. He is a knowledgeable and diligent professor and a leading
scientist in the fields of space variant polarization engineering and I am especially grateful
for his experienced guidance and vision in my research of subwavelength antenna
engineering.
I would also like to thank my committee members, Dr. Partha Banerjee, Dr. Andrew
Sarangan and Dr. Imad Agha for their continuous support during my Ph.D. research. I am
very grateful for their valuable revision advice on my dissertation manuscript.
I would like to thank the former members of Dr. Zhan’s group, including Dr Wei Han, Dr.
Wen Cheng, Dr. Weibin Chen, and Dr. Zhi Wu. I have received a lot of help from them
since I came to the United States to pursue my Ph.D. in 2010. I also want to thank the other
students from Electro-optics Program, including Zhijun Yang, Hongwei Chen, Chuan Ni,
Zhenyu Yang, Sichao Zhou and Yu Bai for their help and support.
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Last but not least, I would like to thank my family. My parents are always there for me.
My special thanks goes to my girlfriend, Yijia Sun. None of this could have happened
without their support.
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TABLE OF CONTENTS
ABSTRACT ....................................................................................................................... iv
DEDICATION……………………………………………………………………………vi
ACKNOWLEDGEMENTS .............................................................................................. vii
LIST OF FIGURES .......................................................................................................... xii
LIST OF TABLES ......................................................................................................... xviii
LIST OF ABBREVIATIONS AND NOTATIONS ........................................................ xix
CHAPTER 1 INTRODUCTION ........................................................................................ 1
CHAPTER 2 MODIFIED BOWTIE ANTENNA DESIGNED FOR STRONG
BROADBAND FIELD ENHANCEMENT ....................................................................... 5
2.1 Background of Bowtie Antenna ........................................................................... 5
2.2 Geometry and Simulation Method for Bowtie Antenna on lithium niobate
substrate ........................................................................................................................... 7
2.3 Modified Bowtie Antenna Based on LC Circuit Principle .................................. 9
2.4 Substrate effect on field enhancement due to Fano Resonance ......................... 12
2.5 Application: Integrated Photonic Electromagnetic Field Sensor Based on
Broadband Bowtie Antenna Coupled Silicon Organic Hybrid Modulator ................... 18
2.5.1 Introduction ...................................................................................................... 18
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2.5.2 Practical design and simulation results ............................................................. 20
2.5.3 Characterization ................................................................................................ 24
2.6 Application: Silica/Electro-optic Polymer Optical Modulator for MMW
Receiving ....................................................................................................................... 25
2.7 Systematic study for Bowtie Antenna on transparent glass and SOI substrate .. 27
2.8 Summary ............................................................................................................ 33
CHAPTER 3 SLOT-ANTENNA-BASED METALLIC METASURFACE
STRUCTURES DESIGNED FOR ULTRA-LONG OPTICAL NEEDLE FIELD WITH
HIGH PURITY ................................................................................................................. 35
3.1 Background of Optical Needle Field Generation ............................................... 35
3.1.1 Introduction to Optical Needle Field ................................................................ 35
3.1.2 Calculation of Electric Field at Pupil Plane...................................................... 36
3.1.3 Pupil Filter Discretization ................................................................................. 40
3.2 Slot-antenna-based Metallic Metasurface Structures ......................................... 42
3.2.1 Background of Metasurfaces ............................................................................ 42
3.2.2 Slot-antenna-based Metasurface Structures design .......................................... 43
3.2.3 Function test experiment results and discussion............................................... 50
3.3 Summary ............................................................................................................ 56
CHAPTER 4 HYBRID REFLECTION TYPE METASURFACE OF NANO-
ANTENNAS DESIGNED FOR OPTICAL NEEDLE FIELD GENERATION .............. 58
4.1 Introduction ........................................................................................................ 58
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